195 citations · 1.1k across the 29 of their papers we have counts for
17 papers · 1 filter
Observability of the total inflationary expansion
Sergei Winitzki
I consider the question of possible observability of the total number of e-folds accumulated during the epoch of inflation. The total number of observable e-folds has been previous…
Geometro-thermodynamics of tidal charged black holes
László Árpád Gergely, Narit Pidokrajt, Sergei Winitzki
Tidal charged spherically symmetric vacuum brane black holes are characterized by their mass m and tidal charge q, an imprint of the 5-dimensional Weyl curvature. For q>0 they are…
Reheating-volume measure in the landscape
Sergei Winitzki
I recently proposed the "reheating-volume" (RV) prescription as a possible solution to the measure problem in "multiverse" cosmology. The goal of this work is to extend the RV meas…
Reheating-volume measure for random-walk inflation
Sergei Winitzki
The recently proposed "reheating-volume" (RV) measure promises to solve the long-standing problem of extracting probabilistic predictions from cosmological "multiverse" scenarios i…
A volume-weighted measure for eternal inflation
Sergei Winitzki
I propose a new volume-weighted probability measure for cosmological "multiverse" scenarios involving eternal inflation. The "reheating-volume (RV) cutoff" calculates the distribut…
Attractor scenarios and superluminal signals in k-essence cosmology
Jin U Kang, Vitaly Vanchurin, Sergei Winitzki
Cosmological scenarios with k-essence are invoked in order to explain the observed late-time acceleration of the universe. These scenarios avoid the need for fine-tuned initial con…
Predictions in eternal inflation
Sergei Winitzki
In generic models of cosmological inflation, quantum fluctuations strongly influence the spacetime metric and produce infinitely many regions where the end of inflation (reheating)…
Self-reproduction in k-inflation
Ferdinand Helmer, Sergei Winitzki
We study cosmological self-reproduction in models of inflation driven by a scalar field with a noncanonical kinetic term (-inflation). We develop a general criterion for the…
Cosmological particle production and the precision of the WKB approximation
Sergei Winitzki
Particle production by slow-changing gravitational fields is usually described using quantum field theory in curved spacetime. Calculations require a definition of the vacuum state…
Time-reparametrization invariance in eternal inflation
Sergei Winitzki
I address some recently raised issues regarding the time-parametrization dependence in stochastic descriptions of eternal inflation. To clarify the role of the choice of the time g…
Drawing conformal diagrams for a fractal landscape
Sergei Winitzki
Generic models of cosmological inflation and the recently proposed scenarios of a recycling universe and the string theory landscape predict spacetimes whose global geometry is a s…
Creation of massive particles in a tunneling universe
Jooyoo Hong, Alexander Vilenkin, Serge Winitzki
We examine the particle production during tunneling in quantum cosmology. We consider a minisuperspace model with a massive, conformally coupled scalar field and a uniform radiatio…
Particle creation in a tunneling universe
J. Hong, A. Vilenkin, S. Winitzki
An expanding closed universe filled with radiation can either recollapse or tunnel to the regime of unbounded expansion, if the cosmological constant is nonzero. We re-examine the…
Null Energy Condition Violations in Eternal Inflation
Serge Winitzki
The usual scenario of ``eternal inflation'' involves an approximately de Sitter spacetime undergoing upward fluctuations of the local expansion rate . This spacetime requires fr…
The eternal fractal in the universe
Serge Winitzki
Models of eternal inflation predict a stochastic self-similar geometry of the universe at very large scales and allow existence of points that never thermalize. I explore the fract…
Effective noise in stochastic description of inflation
S. Winitzki, A. Vilenkin
Stochastic description of inflationary spacetimes emulates the growth of vacuum fluctuations by an effective stochastic ``noise field'' which drives the dynamics of the volume-smoo…
Predictability crisis in inflationary cosmology and its resolution
Vitaly Vanchurin, Alexander Vilenkin, Serge Winitzki
Models of inflationary cosmology can lead to variation of observable parameters ("constants of Nature") on extremely large scales. The question of making probabilistic predictions…